Method for determining solubility of pre-oxidized fiber

Abstract

The invention relates to a method for determining the solubility of pre-oxidized fibers in the field of carbon fibers. The determination method comprises the following steps: (1) drying pre-oxidized fibers, weighing, and recording the weight as G1; (2) performing a DMF soaking process; (3) performing a formic acid soaking process; (4) cleaning, drying and weighing, recording the weight as G2, andcalculating; according to the method, an unconverted structure can be better dissolved, a more accurate result is obtained, the result consistency is good, the influence of human factors on the resultis small, and production can be better served.

Description

technical field

[0001] The invention relates to the field of carbon fibers, and more particularly, relates to a method for measuring the solubility of pre-oxidized fibers. Background technique

[0002] Pre-oxidation is a very important intermediate process in the production of acrylonitrile-based carbon fibers, and it is a bridge to convert PAN precursors into carbon fibers. The pre-oxidation process affects the yield and quality of carbon fibers. During the pre-oxidation process, different physical and chemical changes occur in the precursor, and the molecular structure also undergoes transformation. After intramolecular cyclization and intermolecular crosslinking, the acrylonitrile group The linear macromolecular chain of the original silk is transformed into a heat-resistant trapezoidal structure. Due to the uneven radial distribution of the fiber density, the pre-oxidized silk can easily form a skin-core structure, that is, the fiber surface density is higher, and the in...

Examples

Embodiment 1

[0034] The assay method comprises the following steps:

[0035] (1), drying pre-oxidized fiber, weighing:

[0036] Weigh about 2.5g of the pre-oxidized wire sample, dry it in a blast drying oven at 120°C for 2 hours, take it out, weigh it and record the accurate result G1(g);

[0037] (2) DMF soaking process:

[0038] a), put the dried pre-oxygenated silk sample into a beaker, add 100mL (95 grams) of DMF solution, place the beaker on a magnetic stirrer and stir for 100min (at room temperature), after the stirring is completed, use a dropper to absorb the soaked liquid, drop it into the desalinated water, and observe whether there are water-insoluble substances.

[0039] b) Take out the sample, wash and soak with new DMF solution (stirring at the same time) for 30 minutes, use a dropper to absorb the soaked liquid and drop it into the desalinated water, and observe whether there are water-insoluble substances.

[0040] c) Place the soaked sample in step b) in a centrifuge tu...

Embodiment 2

[0058] Many people used the same pre-oxygenated silk sample from Lanzhou Bluestar Fiber Co., Ltd., and used the test method of the present invention described in Example 1 to measure the solubility. The specific results are shown in Table 2 below:

[0059] Table 2

[0060]

[0061] (Remarks: Calculate the relative error of each person with the average of all the results (1.717) as the true value)

[0062] From the experimental results of Example 1 and Example 2, it can be seen that using the method of the present invention, the CV value of the result is all small; different personnel use this method to measure, and the results have good consistency.

[0063] The solubility determination method of the pre-oxidized fiber of the present invention can accurately reflect the degree of oxidation of the pre-oxidized fiber through a large amount of experimental measurement data, the result of the method is relatively accurate, the CV% value is small, and the influence of human fact...

technical field

[0001] The invention relates to the field of carbon fibers, and more particularly, relates to a method for measuring the solubility of pre-oxidized fibers. Background technique

[0002] Pre-oxidation is a very important intermediate process in the production of acrylonitrile-based carbon fibers, and it is a bridge to convert PAN precursors into carbon fibers. The pre-oxidation process affects the yield and quality of carbon fibers. During the pre-oxidation process, different physical and chemical changes occur in the precursor, and the molecular structure also undergoes transformation. After intramolecular cyclization and intermolecular crosslinking, the acrylonitrile group The linear macromolecular chain of the original silk is transformed into a heat-resistant trapezoidal structure. Due to the uneven radial distribution of the fiber density, the pre-oxidized silk can easily form a skin-core structure, that is, the fiber surface density is higher, and the in...

Examples

Embodiment 1

[0034] The assay method comprises the following steps:

[0035] (1), drying pre-oxidized fiber, weighing:

[0036] Weigh about 2.5g of the pre-oxidized wire sample, dry it in a blast drying oven at 120°C for 2 hours, take it out, weigh it and record the accurate result G1(g);

[0037] (2) DMF soaking process:

[0038] a), put the dried pre-oxygenated silk sample into a beaker, add 100mL (95 grams) of DMF solution, place the beaker on a magnetic stirrer and stir for 100min (at room temperature), after the stirring is completed, use a dropper to absorb the soaked liquid, drop it into the desalinated water, and observe whether there are water-insoluble substances.

[0039] b) Take out the sample, wash and soak with new DMF solution (stirring at the same time) for 30 minutes, use a dropper to absorb the soaked liquid and drop it into the desalinated water, and observe whether there are water-insoluble substances.

[0040] c) Place the soaked sample in step b) in a centrifuge tu...

Embodiment 2

[0058] Many people used the same pre-oxygenated silk sample from Lanzhou Bluestar Fiber Co., Ltd., and used the test method of the present invention described in Example 1 to measure the solubility. The specific results are shown in Table 2 below:

[0059] Table 2

[0060]

[0061] (Remarks: Calculate the relative error of each person with the average of all the results (1.717) as the true value)

[0062] From the experimental results of Example 1 and Example 2, it can be seen that using the method of the present invention, the CV value of the result is all small; different personnel use this method to measure, and the results have good consistency.

[0063] The solubility determination method of the pre-oxidized fiber of the present invention can accurately reflect the degree of oxidation of the pre-oxidized fiber through a large amount of experimental measurement data, the result of the method is relatively accurate, the CV% value is small, and the influence of human fact...

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